Devyani Food Industries Ltd.
The Challenge
Designing a Zero-Discharge WWTP for Highly Complex Bakery Wastewater
Devyani Food Industries Ltd., the manufacturer behind the Creambell brand, was establishing a new greenfield biscuit, rusk, and bakery manufacturing facility at the SIDCO Industrial Area, Bhagthali, Kathua, Jammu. As part of the project, Spans Envirotech was engaged to design a comprehensive Wastewater Treatment Plant (WWTP) to handle the full water balance of the new facility — combining industrial process wastewater (ETP) and communal sewage (STP) into a single integrated treatment solution.
The facility's manufacturing processes — baking, ingredient mixing, line washing, and utility operations — generate highly complex industrial wastewater characterised by extremely elevated organic loads. With COD values up to 20,000 mg/L and BOD as high as 11,000 mg/L, the process effluent ranks among the most challenging wastewater streams in the food manufacturing sector. Elevated fats, oils, and grease (FOG up to 400 mg/L) from biscuit production add further treatment complexity, demanding a carefully sequenced multi-stage treatment approach.
Beyond treatment performance, the facility's location in Jammu & Kashmir introduced a strict regulatory framework — compliance with Environment Protection Rules 1986, National Green Tribunal (NGT) stipulations, and J&K State Pollution Control Board (SPCB) standards was non-negotiable. The client also required a zero liquid discharge (ZLD) design to maximise water conservation and eliminate any environmental discharge from the facility.
Key Issues:
- !Industrial wastewater with extremely high organic load — COD up to 20,000 mg/L and BOD up to 11,000 mg/L from flour, sugar, and baking fats
- !Multiple distinct wastewater streams requiring separate treatment pathways (ETP for industrial effluent + STP for communal sewage)
- !Zero liquid discharge requirement with 100% treated water reuse for cooling towers, horticulture, and toilet flushing
- !Compliance with Environment Protection Rules 1986, NGT stipulations, and J&K SPCB discharge standards
The Solution
Integrated ETP + STP System with Anaerobic SMAR and Advanced Tertiary Treatment
Spans Envirotech designed a fully integrated 261 m³/day treatment system combining a dedicated Effluent Treatment Plant (ETP) for the 156 m³/day industrial stream and a Sewage Treatment Plant (STP) for the 90 m³/day communal wastewater, with utility flows handled separately. The two systems were designed with independent treatment trains to match the very different characteristics of each stream, while sharing common infrastructure where appropriate to optimise capital and operating costs.
The ETP treatment train was engineered around the high-strength organic load. A Dissolved Air Flotation (DAF) system provides effective physico-chemical pre-treatment, removing suspended solids, fats, oils, and grease before biological treatment. The clarified effluent then passes through a Submerged Media Anaerobic Reactor (SMAR), which performs primary biological degradation and recovers biogas (approximately 60% methane) as an energy by-product — significantly reducing the organic loading on the downstream aerobic stages. Two-stage aerobic biological treatment polishes the effluent to meet discharge standards, with Ultrafiltration (UF) and Sand/Activated Carbon Filtration providing tertiary quality and chlorination completing the treatment chain.
The STP design uses a simpler, purpose-optimised train: buffer collection, two-stage aerobic biological treatment, dual media filtration, and chlorine disinfection to produce treated water meeting STP discharge standards. All treated water from both systems is returned to the facility for reuse — cooling towers, horticulture, and toilet flushing — delivering a true zero liquid discharge facility with no effluent released to the environment.
Technologies Deployed:
Implementation Timeline:
Phase 1: Wastewater Characterisation & Process Design
Detailed characterisation of all wastewater streams — industrial ETP (156 m³/day, COD 20,000 mg/L, BOD 11,000 mg/L) and communal STP (90 m³/day) — followed by development of the full process design basis, treatment train selection, and water balance optimisation for zero liquid discharge.
Phase 2: ETP Design — DAF + SMAR + Aerobic Treatment + Tertiary
Engineering design of the industrial Effluent Treatment Plant: DAF system for FOG and TSS removal, SMAR anaerobic reactor for primary organic reduction and biogas recovery, two-stage aerobic biological treatment, and UF + sand/activated carbon tertiary polishing with chlorination.
Phase 3: STP Design — Aerobic Treatment + Dual Media Filtration
Engineering design of the Sewage Treatment Plant: buffer collection, two-stage aerobic biological treatment sized for 90 m³/day communal sewage, dual media filtration, and chlorine disinfection to meet STP treated water quality standards.
Phase 4: Water Balance Optimisation for Zero Liquid Discharge
Integration of ETP and STP treated water streams into the facility water balance — allocating 100% of the 256 m³/day combined treated output to cooling towers, horticulture irrigation, and toilet flushing applications, eliminating any liquid discharge from the site.
The Results
Zero Discharge System Designed to Exceed Regulatory Standards
99%+
BOD Removal
Industrial BOD reduced from 11,000 mg/L to <30 mg/L — exceeding inland surface water discharge standards
99%
COD Removal
COD reduced from 20,000 mg/L to <200 mg/L through integrated anaerobic and aerobic treatment
100%
Water Reuse
Zero liquid discharge design — all 256 m³/day treated water recycled for cooling towers, horticulture and toilet flushing
261 m³/day
Treatment Capacity
Combined ETP (156 m³/day) and STP (90 m³/day) system sized for full facility water balance
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